Castration of Piglets – Position Statement

September 21, 2016

Position

The Canadian Veterinary Medical Association (CVMA) holds that surgical castration of piglets to prevent boar-taint and aggression in post-pubertal boars is a painful procedure at any age and effective anesthesia and analgesia is required for all ages of pigs. The CVMA encourages development and implementation of practical analgesic and anesthetic protocols for, and alternatives to, swine castration.

Summary

Castration of piglets is used to help avoid unwanted behaviour and prevent some quality issues in pork.

Background

In North America, hogs are marketed between 5 and 6 months of age at approximately 120 kg live weight (265 lb). Intact market weight boars are post-pubescent and sexual activity and aggression can cause injury, pain, and discomfort. Castration of piglets is a method of avoiding unwanted post-pubertal behaviour and controlling boar taint, an unpleasant odour and flavour of cooked pork.

Commonly, surgical castration of piglets is performed by producers. This surgical procedure is acutely painful and involves the incision of skin and manipulation of sensitive tissues with subsequent inflammation (1-3). There is a risk of haemorrhage, infection, and evisceration (4).

Discomfort post-castration can last for 2 days (5). Local anesthetic injected into the testis and subcutaneously into the scrotum reaches the spermatic cord within minutes (6) and can reduce some of the responses to castration (7,8).

Although there is no effect of age on the responses of piglets to the pain of castration (9), the revised code of practice for producers requires the administration of analgesia for castration of all ages, and anesthesia and analgesia for piglets older than 10 days of age (10).

Some non-steroidal anti-inflammatory drugs (NSAIDS) have been approved for use in piglets in Canada and can reduce post-operative pain responses (11). The CVMA recognizes that pig producers incur additional expense owing to the cost of pain medication and time taken to administer.

The administration of only analgesia (rather than effective anesthesia and analgesia) is less time-consuming than administering local anesthesia and waiting for it to take effect (12). Although the strength of the evidence has been questioned (13) and there is stress associated with extra handling and the administration of the local anesthetic (2), the administration of both local anesthesia and analgesia is necessary to effectively reduce the pain response during and after surgical castration (14-16).

Veterinarians should provide training to producers on the recognition of cryptorchidism and herniation, and appropriate handling, surgical procedures, and anesthetic and analgesia protocols to follow when undertaking castration.

Pig Code of Practice Scientific Committee. Code of Practice for the Care and Handling of Pigs: Review of Scientific Research on Priority Issues. Lacombe (Alberta): National Farm Animal Care Council, 2012.